Virus? Lol, I use linux.
Really, it doesn't make any practical difference. Facebook walls are constantly spammed intentionally by those stupid application posts that people send en-masse to everyone. "I ANSWERED A QUESTION! WOULD NICK HIT A CHILD? CLICK HERE TO SEE WHAT I ANSWERED!", "I FOUND A ABANDONED BLACK PIG IN FARMVILLE, WILL YOU ADOPT HIM‽"
And then there are those chain letters that people constantly spam each other with: "(randomunicodecharacters)I hate you you are an idiot oh but i lied i love u u are my best friend send this to all your best friends(randomunicodecharacters)". It is incredibly irritating, and whenever I receive a post like that, it is an instant block for the spammer.